There are many good calibration objects available in the cyber ether but I thought I would make a contribution to the pool. Most of the items I print are functional/mechanical in nature so accuracy is very import as the parts must fit well with their respective mates. This little calibration object allows me to print a part that provides all the feedback I typically need regarding feature form accuracy. Its not the object I begin the calibration process with but it is the finally test article. At 3600 mm/min print speed, 0.2 mm layer height, 0.4 mm bead width, 35% infill, 2 outer shells, 3 top and bottom layers it will print in 22 minutes. The thin tab off the large circle feature is set to 4X nominal bead width as I print with 2 perimeter walls. The rectangular area of the part is 5mm tall, the cylinder is an additional 5mm.